This application claims the priority of Korean Patent Application No. 2002-62696 filed Oct. 15, 2002 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a rear projection screen and a projector adopting the same, and more particularly, to a rear projection screen which can reduce reflection of external light and emit functional substance to an audiovisual space, and a projector adopting the same.
2. Description of the Related Art
In general, projectors provide images by generating the image in an image forming unit and projecting the same onto a screen. The projectors are classified into front projection projectors and rear projection projectors according to the method of magnifying and projecting an image onto a screen.
Referring to FIG. 1, a typical rear projection projector includes a cabinet 10, a screen 20 installed on the front surface of the cabinet 10 and where an image is formed, an image forming unit 11, such as a cold CRT, installed in the cabinet 10 and generating and projecting an image, a projection lens unit 13 magnifying and projecting the image emitted by the image forming unit 11, and a reflection mirror 15 reflecting the image input from the projection lens unit 13 toward the screen 20. In the rear projection projector having the above structure, an image projected in the rear of the screen 20 and formed on the screen 20 is viewed in front of the screen 20, that is, outside the cabinet 10.
Referring to FIG. 2, the conventional rear projection screen 20 includes a Fresnel lens 21 concentrating a divergent light input from the projection lens unit 13 to be a parallel beam, a lenticular lens 23 arranged on a front surface of the Fresnel lens 21 and forming an image by focusing light passing through the Fresnel lens 21, and a protective panel 25 installed on a front surface of the lenticular lens 23.
The protective panel 25 protects the Fresnel lens 21 and the lenticular lens 23 from scratching and contamination and is used to improve contrast of an image. Meanwhile, when an external light source is present and an audiovisual space is bright, the protective panel 25 causes a surface reflection with respect to an external light so that the quality of an image is deteriorated.
In consideration of the above problem, the subject applicant filed Korean Patent Application No. 98-28422 on 14 Jul. 1998. According to the Korean application, as shown in FIG. 3, the protective panel 25 includes an external light reflection reducing portion 27 which can reduce reflection of light input from an external light source installed outside a projector. The external light reducing portion 27 changes a reflection angle of the light input from the external light source and makes the light diffusively reflected, so that reflection light proceeding toward a viewer is reduced.
However, this projection screen has no additional function other than the external light reflection reduction.